B3: Correlations in antiferromagnets

The study of phase transitions and strongly correlatedbehavior with the help of coupled spin systems has along tradition ever since the proposal of the Isingmodel. Modern research focuses on antiferromagneticmodel systems in order to understand the genericbehavior of a variety of quantum phase transitions andmore complicated order parameters, includingtopological phases, supersolid phases, and spin-liquidphases. Even though the spin degrees of freedom aretypically quite simplified, it is possible to tune theinteractions and fields in order to study theuniversal signatures for a large range of stronglycorrelated effects, which can then be generalized tomore realistic experimental setups. Interacting spinmodels are naturally closely related to interactingbosonic systems in reduced dimensions, which are ofexperimental relevance in the ultra-cold gasescommunity.

Specific topics which are currently covered in thisproject are for example: - The magnetocaloric effectacross phase boundaries - The role of frustration nearphase transitions - Exotic phases on triangular andKagome lattices

Methods include numerical simulations and fieldtheoretical calculations. Active collaborations whichlikely will result in common papers currently takeplace with projects A5, A8, B1, B2, and B7.